The invention relates to an opening roller construction having a plurality of teeth, each tooth having a tooth throat, a tooth face, a back, and lateral profiles between the tooth face and the back, and a vertical angle of no more than 30.degree. and a front angle of at least 15.degree. being provided
A toothed fitting for an opening roller of the initially mentioned type is known from German Published Application No. 34 39 664 (see also related commonly owned pending U.S. application Ser. No. 191,402, filed May 9, 1988 as a Continuation-in-Part of U.S. Application Ser. No. 793,122, filed Oct. 30, 1985). In this case, the teeth are produced in that they are machined out of solid material by the working-in of grooves extending essentially in axial direction and of grooves extending essentially in circumferential direction. By means of this method of production, it is possible to adapt the shape of the teeth to specific tasks and particularly also to the fiber material to be processed.
Other commonly assigned patents and patent applications which relate to opening roller constructions include (i) pending U.S. Application Ser. No. 196,688, which is a Continuation-in-Part of U.S. Application Ser. No. 088,973, filed Aug. 24, 1987, which is in turn a Continuation of Application Ser. No. 731,272, filed May 7, 1985; (ii) U.S. Pat. 4,646,389; and (iii) U.S. Pat. No. 4,715,777.
See also commonly assigned U.S. Pat. Application Ser. No. 237,330, filed Aug. 29, 1988, based on German Patent Application No. P 37 30 297.3, filed Sept. 10, 1978 in Germany.
An object of the invention is to provide a toothed fitting of the initially mentioned type with improved penetration into the fiber material to be opened up, which fiber material is offered in the manner of a fiber beard to the opening roller equipped with the toothed fitting.
This object is achieved in that the tooth tips are chamfered and form cutting edges which extend essentially in the travel direction of the teeth.
Tooth tips that are constructed in this manner penetrate more easily into the fiber material which consists essentially of fibers that are aligned in parallel to one another in the travel direction of the teeth. As a result, it is achieved that the tooth tips, on the one hand, cause little damage when they penetrate into the fiber material, and, on the other hand, also do not press the fiber material out of the area of the toothed fitting.
In a further development of preferred embodiments of the invention, it is provided that the lateral profiles of the teeth, approximately in the area of the last quarter of their radial height, have areas that are chamfered in the manner of cutting edges. Tooth shapes of this type can be ground in a manner that is similar to methods used in the case of saw blades or milling tools. For reasons of stability, it is advantageous according to especially preferred embodiments for the areas of the lateral profiles that are chamfered in the manner of cutting edges to enclose between one another an angle of approximately 35.degree. to 50 .degree. As a result, a compromise can be achieved between the chamfering in the manner of cutting edges and sufficient stability.
In a further development of preferred embodiments of the invention, it is provided that the cutting edges, have a width transversely to the travel direction, of approximately 0.1 mm. It is also provided that the cutting edges, in the travel direction, have a length of at least 2 mm. By means of teeth of this type, which have almost the shape of needles, a good opening-up of the fiber material can be achieved.
In a further development of preferred embodiments of the invention, it is provided that the teeth are worked out of the exterior surface of a ring by the machining in of grooves extending essentially in axial direction and of grooves extending essentially in circumferential direction, in which case the grooves extending essentially in circumferential direction are deeper than the grooves extending essentially in axial direction. As a result, recessed lanes extending essentially in circumferential direction can be created between the teeth which permit an advantageous conveying of the combed-out fibers. In this case, the grooves extending in circumferential direction are preferably 1/3deeper than the other grooves.
In a further development of preferred embodiments of the invention, it is provided that at least the teeth are nitrided. This nitriding has the advantage that a relatively soft steel material an be used for the production of the teeth which, after the nitriding process --for example, in contrast to case hardening, can be used without any refinishing because no drafts or structural changes or the like occur at the surface. An additional tempering of the tooth core is possible for a better carrying of the nitrided layer. The surface quality of the nitrided layer has a positive effect on the opening-up of the fibers.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.